JPH08219639A - Dryer for veneer - Google Patents

Abstract

PURPOSE: To provide an intermittent conveyance heating board pressing type dryer in which the steam generated from a veneer can be smoothly dispersed without impairing the excellence of heat transferring efficiency. CONSTITUTION: A dryer comprises a pair of metal thin plate endless belts so installed at suitable number of rolls as to intermittently feed, a conveying passage of a veneer 10 formed in the opposed intervals of both endless belts, and suitable pairs of heating boards 3a and 4a which can approach at least at the one to the other and separate from the one to the other to be disposed at both sides of the passage, wherein the veneer 10 is heated and dried via the belts by the boards 3a and 4a while intermittently conveying the veneer 10 by the belts. Many pores 11 and 12 are formed in a dispersed state at the entire periphery of the belt, and suitable stripes of narrow grooves 13 and 13 are provided on the heating surfaces of the boards 3a and 4a opposed to the belts having the pores 11 and 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a drying device used for drying veneer veneer (hereinafter simply referred to as veneer).

[0002]

2. Description of the Related Art The applicant of the present invention has previously described, for example, "a method for correcting an endless track in a veneer veneer drying apparatus" (Japanese Patent Laid-Open No. Sho 63-63).
No. 226588), a pair of metal thin plate endless belts are erected on an appropriate number of rolls so as to be able to run intermittently, and a single plate conveyance path is formed within the facing interval of both endless belts, and the conveyance is performed. It consists of a suitable number of pairs of heating plates, at least one of which can approach and separate from the other, on both sides of the road. Drying device of the type that heats and dries the veneer through the strip,
Although an improvement plan has been disclosed for a so-called intermittent transfer hot platen press type drying device, the need for further improvement has gradually become clear as the device is put into practical use.

[0003]

That is, one of the characteristics of this type of drying apparatus is that the heating plate presses the veneer entirely through the endless strip made of a thin metal plate, and directly presses the veneer. Although the heat transfer efficiency is excellent due to the heat transfer heating, on the other hand, the entire pressurization of the veneer by the heating plate is also a factor that hinders the vapor emission from the veneer. The vapor is not necessarily diffused smoothly, resulting in an adverse effect of delaying drying unnecessarily.

Furthermore, as described above, if the vapor is not diffused smoothly from the veneer due to the overall pressurization of the veneer by the heating plate, the pressure inside the veneer is higher than the atmospheric pressure. High-pressure steam remains, and when the residual steam is rapidly (explosively) released from the veneer as the pressure applied by the heating plate is released, it exists inside the veneer. Any of the adverse effects is one of the factors that reduce the practicability of the apparatus, such as the occurrence of the adverse effects of damaging the veneer by the weak points such as small cracks and knots.

On the other hand, in place of the above-mentioned endless belt made of a thin metal plate, if an endless wire net as disclosed in, for example, "Veneer Dryer" (Japanese Patent Publication No. 48-654) is used,
Since the steam is smoothly emitted from the innumerable gaps of the wire netting, there is no fear of causing the above-mentioned harmful effects, but on the other hand, the main body of heating by the heating plate is indirect radiation heating through the gaps of the wire netting. Therefore, as compared with the case of heat transfer heating, it is unavoidable that the heat transfer efficiency is significantly deteriorated, and the original advantages of this type of device cannot be fully utilized.

[0006]

The present invention was developed in order to solve the drawbacks of the conventional apparatus of this kind, and specifically, a pair of endless belts made of a thin metal plate constituting the drying apparatus. Of the above, at least any one of the endless strips is formed over a whole peripheral surface thereof with a large number of small holes dispersedly, and at least one heating plate of the heating plate facing the endless strip having the small holes is formed on the heating surface. We propose a drying device characterized by having a proper number of narrow grooves.

[0007]

According to the drying device having the above-described structure, the main body of heating by the heating plate is the heat transfer heating through the endless belt made of a thin metal plate, so that the heat transfer efficiency is excellent. , The original advantages of this kind of device are fully utilized, and at least a part of the steam generated from the veneer due to heating is generated by the endless small holes and the narrow grooves of the heating plate. Through, it will be smoothly diverged. Therefore, it is possible to prevent or significantly reduce the possibility that the drying may be delayed unnecessarily or the veneer may be damaged as in the conventional apparatus.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to an example illustrated in the drawings. FIG. 1 is a side view of a drying apparatus according to the present invention, and FIG. 2 is a portion A in FIG. FIG. 3 is a partially cutaway enlarged view of FIG. 3, and FIG. 3 is a partial perspective explanatory view of the endless belt used in the device of FIG. 1.

In the figure, 1 and 2 are a pair of endless strips made of a thin metal plate, in which a large number of small holes 11 and 12 are formed in a dispersed manner over the entire circumferential surface of each, and respectively. Are erected in a facing manner via a plurality of rolls 1a, 1b, 1c and 2a, 2b, 2c, and a single-plate conveying path is formed within the facing interval. -The intermittent drive source 5 including an electric motor with a clutch and brake unit is actuated to intermittently travel in the direction of the arrow shown in the figure via the rolls 1b and 2b.
Is intermittently transported.

Reference numerals 3a, 3b, 3c, and 3d denote upper heating plates fixed to a machine frame (not shown) so as to be fixedly positioned above the veneer conveyance path.・ When the lower heating plates 4a, 4b, 4c, 4d, which will be described later, are being heated to an appropriate temperature via a heat source such as an electric heater, they cooperate with the lower heating plates 4a, 4b, 4c, 4d. , The single plate 10 is clamped through the endless belts 1 and 2 to heat the single plate 10.
dry.

4a, 4b, 4c, and 4d are lifting devices composed of a fluid cylinder, a crank mechanism, a cam mechanism, a link mechanism, and the like, which are fixed to the machine frame so as to be movably positioned below the single plate transport path. 6a, 6b, 6c, and 6d are lower heating plates each of which is individually lifted and lowered, and is heated to an appropriate temperature via a heat source such as heating steam, heating oil, and an electric heater. With the control of the vessel 7, when intermittently rising, the single plate 10 is clamped through the endless belts 1 and 2 in cooperation with the upper heating plates 3a, 3b, 3c and 3d. The veneer 10 is heated and dried.

Further, the upper heating plates 3a, 3b,
Of the 3c and 3d and the lower heating plates 4a, 4b, 4c, and 4d, at least the upper heating plate 3a and the lower heating plate 4a (and, if necessary, all of the other heating plates), respectively. A suitable number of fine grooves 13 and 14 are formed on the heating surface and face any of the numerous small holes 11 and 12 formed in the endless belts 1 and 2.

Reference numeral 7 denotes a controller for controlling the operation of at least the intermittent drive source 5 and the lifting / lowering devices 6a, 6b, 6c, 6d. Specifically, when operating the intermittent drive source 5,
When the operation of the lifting devices 6a, 6b, 6c, 6d is stopped, and when the operation of the intermittent drive source 5 is stopped, the lifting devices 6a, 6b, 6c, 6d are operated intermittently to lower the heating plate 4a.・ 4b, 4c, and 4d are controlled so as to rise for a desired time.

Numerals 8 and 9 are tension members for imparting an appropriate tension state to the endless belts 1 and 2 through the rolls 1c and 2c. It is possible to apply a tension state to the endless belts 1 and 2 at all times, but if necessary, a fluid cylinder, a crank mechanism, a cam mechanism, a link mechanism, and the like are used, and control of the controller 7 (control (The circuit is not shown), so that the operation is limited only during the period in which the endless belts 1 and 2 are intermittently run via the intermittent drive source 5, and the tension is applied to the endless belts 1 and 2 only for a predetermined period. It doesn't matter.

The drying device according to the present invention is constructed, for example, as described above, and the veneer 1 from the left side in FIG.
When 0 is loaded, the elevators 6a, 6b, 6c are stopped when the endless belts 1 and 2 are stopped during the process in which the veneer 10 is intermittently transferred along the transfer path along with the intermittent running of the endless belts 1 and 2.・ 6d
However, since the lower heating plates 4a, 4b, 4c, 4d are raised for a desired time, the upper heating plate 3 is connected via the endless belts 1 and 2.
a / 3b / 3c / 3d and lower heating platen 4a / 4b / 4c
Heating with 4d is performed.

Next, the lower heating plates 4a, 4b, 4c, 4
In synchronization with the d falling, the endless belts 1 and 2 travel for a while and then stop, and then the lifting devices 6a, 6b and 6c again.
Since 6d raises the lower heating plates 4a, 4b, 4c, 4d for a desired time, the upper heating plates 3a, 3b, 3c, 3d and the lower heating plates 4a, 4b
Heating by 4c and 4d is performed, and thereafter, by repeating the same operation, the veneer 10 is sequentially dried and eventually carried out to the right side in FIG.

In the device having the above-mentioned structure,
Since the main body of heating by the heating plate is heat transfer heating through the endless belt made of a thin metal plate, the heat transfer efficiency is excellent, and the original advantage of this type of device is fully utilized. Needless to say, at least a part of the steam generated from the veneer due to heating is smoothly diffused through the endless small holes and the narrow grooves of the heating plate. Therefore, it is possible to prevent or significantly reduce the possibility that the drying may be delayed unnecessarily or the veneer may be damaged as in the conventional apparatus.

Even if a small hole is formed only in one of the endless bands, it is still effective. However, in view of the ease of vapor diffusion, the small holes are formed in both endless bands as in the above embodiment. It is preferable to form it, and since the generation rate of steam from the veneer tends to gradually decrease from the initial stage to the final stage of drying, it is necessary to ensure that steam is smoothly diffused at least at the initial stage of drying, as in the above-mentioned embodiment. It is preferable to form fine grooves in the applicable heating plate.

Further, the shape of the small hole is not limited to the round hole as in the above-mentioned embodiment, and although not shown in the drawing, for example, a shape such as a long hole, a square hole, a diamond hole, a hexagonal hole, etc. ,
The point is that it does not matter if the steam flow is supported, and the arrangement form is not limited to the parallel form as illustrated in FIG. 3, but may be the zigzag form as illustrated in FIG. 4 or the illustration is omitted. However, even if it is a little irregular, it is enough that it is formed in a distributed manner over the entire peripheral surface of the endless belt. Of course, the shape of one endless belt and the shape of the other endless belt are different. However, in any case, from the viewpoint of strength, it is preferable to prevent the endless belt from being formed at both ends so as to form a blank and prevent damage from both ends. In FIG. 4, 11a is a small hole and 21 is an endless belt.

Further, the shape of the narrow groove is not limited to the rectangular groove shape as in the above-mentioned embodiment, and although not shown in the drawing, it may be, for example, a semi-round groove shape, a V groove shape, a trapezoidal groove shape or the like. However, the point is that the flow of steam does not matter, and the extended form is not limited to the form illustrated in FIGS. 5 and 6, but is extended in parallel with the veneer conveyance direction, although not shown. The existing form or a form in which a plurality of them intersect each other is essential, and in essence, it suffices that the circulation of steam be supported, and of course, the form of each heating plate need not be the same. Furthermore, each narrow groove does not necessarily have to extend linearly, and need not necessarily be formed over the entire heating surface of each heating plate. In FIG. 6, 3
e is an upper heating plate and 13a is a narrow groove.

Further, from the viewpoint of ensuring the divergence, at least at the portion of the heating plate where the narrow groove is formed, all of the small holes formed in the endless belt should always face one of the narrow grooves. It is preferable to appropriately set the size of the small holes, the interval between the small holes, the width of the narrow groove, the interval between the narrow grooves, the traveling distance of the endless belt, etc. The setting of different intervals is also an example, but even if the setting is not necessarily appropriate and some of the small holes do not face any of the narrow grooves, the Since the small holes can serve as a reservoir for the steam generated from the veneer, they are accordingly useful for promoting drying and preventing damage to the veneer, and due to factors such as intermittent running of the endless belt and slipping of the endless belt. , The temporary condition will be resolved eventually, so it is not necessary to set the preferred settings as described above. It is not necessary to strictly comply, and in addition to the above factors, the relative positions of the small holes and narrow grooves with respect to the single plate also change sequentially due to contraction of the single plate, etc. It is added that the drying of the corresponding local area of the veneer is unlikely to be significantly different from other areas, which is an advantage of the drying apparatus according to the present invention.

However, it is a fact that the heat transfer efficiency of the small holes and the narrow grooves is inferior to the heat transfer efficiency of the other parts. Of course, it is preferable not to set the maximum width per hit to an excessively large value, but it is also preferable to set the aperture ratio of all small holes to the entire peripheral surface of each endless zone and all the fine grooves to all heating surfaces of each heating plate. The open groove ratio should be as low as possible, and the preferable open hole ratio and open groove ratio are 20% or less, and more preferable open hole ratio and open groove ratio are 15% or less.

Of course, the form of the other mechanism that constitutes the entire apparatus is not limited to the form of the above embodiment,
Although not shown, for example, the upper heating plate is supported so as to be able to move up and down, or the upper heating plate and the lower heating plate are both supported so as to be able to move up and down, or for example, each endless band. It is possible to adopt various forms without particular restrictions, such as a form in which the single plate is tensioned in a direction parallel to the conveying path, and further, for example, a form in which the single plate conveying path is formed in a bent shape of three-fold folding. It is possible.

[0024]

As is apparent from the above, according to the drying apparatus of the present invention, the heat transfer efficiency is excellent, and the essential advantage of this type of apparatus is not limited to the above.
As in the case of the conventional device, the risk of causing unnecessary delays in drying or damaging the veneer can be prevented or greatly reduced. Practicality will be further improved.

[Brief description of drawings]

FIG. 1 is a side view of a drying device according to the present invention.

2 is a partially cutaway enlarged view of a portion A in FIG.

3 is a partial perspective explanatory view of an endless band used in the device of FIG. 1. FIG.

FIG. 4 is a partial perspective explanatory view of another example of the endless belt.

5 is a partial plan view of a heating plate used in the apparatus of FIG.

FIG. 6 is a partial plan view of another example of the heating board.

[Explanation of symbols]

 1: Endless band 2: Endless band 3a: Upper heating plate 3b: Upper heating plate 3c: Upper heating plate 3d: Upper heating plate 4a: Lower heating plate 4b: Lower heating plate 4c: Lower heating plate 4d: Lower heating plate 5: Intermittent drive source 6a: Lifting device 6b: Lifting device 6c: Lifting device 6d: Lifting device 7: Controller 8: Tension member 9: Tension member 10: Single plate 11: Small hole 12: Small hole 13: Fine groove 14: Fine groove

Claims (1)

[Claims] 1. A pair of endless strips made of thin metal plates are erected on an appropriate number of rolls so that they can intermittently travel to form a transport path for veneer veneers within the facing interval of both endless strips. A suitable number of pairs of heating plates, at least one of which can approach and separate from the other, are arranged on both sides of the veneer veneer while intermittently conveying the veneer veneer by the pair of endless bands. The veneer veneer is heated through the endless belt by a pair of heating plates.
A drying device for drying, of the pair of endless belts,
Over the entire peripheral surface of at least one of the endless belts, while forming a large number of small holes in a dispersed manner, on the heating surface of at least one heating plate facing the endless belt having the small holes,
A veneer veneer drying device characterized by having an appropriate number of narrow grooves.